knockOut Study

Tap any word on YouTube or Bilibili for instant dictionary lookup while you study a language.

knockOut Study — learn languages by watching what you love. knockOut turns YouTube and Bilibili into an interactive language classroom. When subtitles are on, every word in the subtitle line becomes tappable. Hover for a quick translation. Click for the full dictionary entry — pronunciation, part of speech, example sentences, and synonyms — without ever leaving the video. How it works Enable subtitles in the YouTube or Bilibili player as you normally would. knockOut captures them, processes them, and overlays a tappable version on top. The original video experience stays untouched — you can still pause, seek, and use all native controls. Features Tap any word — instant dictionary lookup with translations, pronunciation (pinyin, romaji), part of speech, and example sentences Hover preview — see the top 3 translations without clicking Save words — build your personal vocabulary list as you watch Phonetic mode — display pinyin or romaji as ruby annotations above every word Draggable overlay — position the subtitle line anywhere inside the video; snaps to center Keyboard shortcuts — A / S / D to jump to previous, repeat, or next subtitle line Fullscreen & cinema support — works in all YouTube and Bilibili layout modes Instant re-play — subtitles are cached locally so revisiting a video loads instantly Supported platforms YouTube (all languages with subtitle support) Bilibili (Chinese, including AI-generated subtitles) Supported study languages Chinese (Mandarin), Japanese, Korean, and more — with romanization support for each. Sign in required knockOut requires a free account at knockoutstudy.com to look up words and save your vocabulary. Privacy knockOut only processes subtitle text you explicitly enable in the player. No audio, no video, no browsing history is collected. See our full privacy policy at knockoutstudy.com/privacy.